1. Field of the Invention
The present invention relates to a computer system, and more particularly, to a computer system providing more general purpose input/output (GPIO) ports without increasing pins on a south bridge.
2. Description of the Prior Art
In this society, computer systems widely used in every industry are playing an important role in many companies for modernization. With improvements such as an increasing data storage density, a rising operation speed, a decreasing production cost, and a friendlier user interface in computer systems, simple computer systems, including a personal computer (PC), can act an information-processing center. Therefore, connecting peripheral devices to a simple computer system to help automate and manage business is deeply expected by many companies. A product monitoring system will be used as an example. While human operation mistakes are unavoidable in affecting the monitoring procedure in a human monitoring system, a detection device for the monitoring system can be connected to a computer system. The detection device can use the computer system to make the monitoring procedure automated. The computer system has great storing and computing capabilities used to analyze the detected product information, which can provide information about production yields and product development. To achieve these objectives, engineers are researching to enhance computer capabilities.
Please refer to FIG. 1, which shows a function block diagram for a computer system 10 according to the prior art. The computer system 10 includes a central processing unit (CPU) 12, a north bridge 20, and a south bridge 30. The CPU 12 is responsible for managing all of the circuits in the computer system 10. The north bridge 20 is electrically connected to the CPU 12 and is responsible for exchanging data of the CPU 12 with memory (such as a random access memory) 18 or with a graphics accelerator 14. A display device (such as a monitor) 16 is electrically connected to the graphics accelerator 14 to provide a video output for the computer system 10. The south bridge 30 is electrically connected to the north bridge 20 to exchange data of the CPU 12 with a peripheral device 22. The peripheral device 22 includes an input device (such as a keyboard or a mouse), a basic input/output system (BIOS), and a nonvolatile memory (such as a hard disk).
The south bridge 30 includes a GPIO port 24 to provide another way for inputting or outputting data through an external device. When using the computer system 10 to exchange data with an external device 28 (such as a detective device mentioned above), the external device 28 uses a GPIO circuit 26 to connect to the GPIO port 24 so as to complete the connection of the external device 28 with the computer system 10. The GPIO circuit 26 is responsible for converting a data signal that is outputted from the external device 28 into a readable format for the GPIO port 24. In addition, the GPIO circuit 26 is responsible for converting a command that is transmitted from the CPU 12 to the GPIO port 24 into a readable format for the external device 28.
Due to the many advances in computer systems, computer systems are capable of processing a lot of data at the same time. In this case, companies expect to use a computer system to exchange data with a plurality of external devices at the same time so as to reduce computerization management costs, integrate data from external devices, and synchronize operations of the external devices. However, while using the computer system 10 of the prior art, the GPIO ports 24 provided by the south bridge 30 are limited in numbers. In addition, as the south bridge is formed in a chip, it is very difficult to increase the number of GPIO ports on the south bridge without the redesign of the chip. The circuits of the south bridge 30 are very complicated because the south bridge has to provide a data exchange path between the GPIO port 24 and the CPU 12, and at the same time the south bridge has to manage operations of the peripheral devices 22 connected to the computer system 10. As a result, a lot of time and cost are required to either redesign or reform the south bridge.